The present invention relates to medical needles, and more particularly to an infusion needle comprising a bio-degradable and bio-absorbable sterile needle tip. Application of the infusion needle of the present invention for intravenous infusion, involves injection, and continuous delivery of medicinal fluid to a blood vessel, for an extended period of time. Application of the infusion needle of the present invention for extravenous infusion, involves injection, and continuous withdrawal of body fluid from organ tissue, for an extended period of time. To one of ordinary skill in the art, an extended period of time, pertaining to infusion applications (i.e., intra- or extra- venous), is a time span longer than that required (typically, less than several minutes) for injection, and delivery or withdrawal of medicinal or body fluid using a hypodermic needle. An extended period of time in infusion applications refers to a time span of at least several minutes, and can be as long as several weeks, whereby the infusion needle remains in the target blood vessel or organ tissue on a continuous basis.
Current clinical infusion applications, (e.g., intravenous infusion, extravenous infusion (catheterization)) are based on the use of appropriately sharp and sterile metal or metal/plastic medical infusion needles. Two configurations of an infusion needle are in current use. The first infusion needle configuration, applicable to both intravenous and extravenous infusion treatments, is constructed of sterile stainless steel, whereby following injection and penetration of the target blood vessel or organ tissue, the metal infusion needle tip remains in direct contact with the blood vessel or organ tissue, as well as the immediate surrounding area of the blood vessel or organ tissue, during the duration of the infusion treatment. The second infusion needle configuration, which is currently applied in intravenous infusion treatment only (i.e., via hypodermic injection), consists of two components: (i) a metal infusion needle, whereby its function is for initial injection and penetration of a blood vessel, and is withdrawn from the patient immediately (i.e., within a few minutes) following penetration of the blood vessel or organ tissue, leaving behind the second component (ii), a (supposedly sterile) plastic tube which shapely fits around component (i), and which remains in the blood vessel from the tine of withdrawal of component (i) and continues to serve as part of the delivery vehicle for the intravenous medicinal fluid.
Following penetration of a blood vessel or organ tissue, medicinal fluid (e.g., saline solution, blood, plasma, hypotonic-, hypertonic-, and isotonic-liquids, and other liquid medications) or body fluid (e.g., urine), is continuously administered into the blood vessel, or continuously withdrawn from organ tissue, through the remaining metal or plastic hollow cylinder part of an infusion needle. Success in treatment of a patient via infusion depends, among other factors, on the continuity, stability, and sterility of the medicinal or body fluid flow, which itself depends upon the absence of discontinuities, obstructions, or the presence of microorganisms in the upstream fluid supply or reservoir and/or tubing carrying the fluid to or from the infusion needle, located in the blood vessel or the organ tissue. Additionally, important to the success of infusion treatment, is the continuity, stability, and sterility of the fluid flow downstream from the intra- or extra- venous infusion needle, i.e., downstream from the location of the infusion needle, leading to or away from, and including the area surrounding the medicinal or body fluid flowing into or out of, the targeted blood vessel or organ tissue, respectively. Success of an infusion treatment depends strongly upon the status of the junction formed between the infusion needle tip and the blood vessel or organ tissue, and the fluid flow through such a junction.
In clinical infusion treatment applications involving the use of the first described infusion needle configuration (i.e., intra- or extra- venous infusion), an undesirable event, which commonly occurs, is movement of the metal infusion needle, within the blood vessel or organ tissue. Movement of the infusion needle tip is a consequence of normal patient movement. Such movement within the patient (i.e., blood vessel or organ tissue) typically results in some degree of blood vessel or tissue damage and possible hemathomasis (i.e., condition of internal hemorrhage), in addition to considerable pain to the patient. In clinical infusion treatment applications involving the use of the second described infusion needle configuration (i.e., intravenous infusion), it is common for foreign microorganisms to be associated with the plastic tube component which remains inside the blood vessel for the duration of an infusion treatment. Exposure of a blood vessel (and ultimately, a patient's bloodstream) to foreign microorganisms may lead to infection and other complications in a patient, requiring replacement of the infusion needle (in such a case, typically, requiring a change in location of the infusion needle), resulting in significant interuption in the infusion treatment, inconvenience, and possibly unnecessary pain to a patient. Clearly, medical infusion needles in current use have limitations and potential health hazards associated with them, due to the sharpness and potential non-sterility of infusion needle tips.
Currently, no modified needle tip for infusion (intra- or extra- venous) is available which minimizes or eliminates the problems of pain or hemathomasis hazard associated with movement of metal infusion needles or metal infusion needle tips. However, certain modified (e.g., bio-absorbable, self-destructive) medical needle tips have been designed, which are specific to hypodermic syringe or biopsy applications, where there is concern of accidental contamination and/or transmission of healthy patients and health care workers with viruses and diseases, via re-use or accidental use of contaminated hypodermic needles. These inventions attempt to solve the problem of illicit drug users who regularly share needles, which may result in the transmission of viruses and diseases from the bloodstream. However, none of these inventions attempts to prevent internal injury due to infusion needle or needle tip movement during infusion treatment.
For example, U.S. Pat. No. 4,976,704 is based on a hypodermic needle containing a moisture soluble alumnium alloy tip, which, following withdrawal of the needle from the patient, the needle tip automatically dissolves. The patent includes the option in the design of the needle tip, to be dissolvable after single use, or following multiple injections over a period of a few minutes for delivery of local anesthetic at several locations before rendered non-functional. The use of a moisture soluble aluminum alloy in a needle tip for intra- or extra- venous infusion applications, is clearly undesirable, due to the poisonous effect of aluminum in the bloodstream or organ tissue, at the level associated with standard infusion needle tips. No teaching is made for using the described aluminum based needle tip for an infusion application.
Another approach in the modification of medical needle tips, for use in prevention of accidental disease transmission, is taught in U.S. Pat. No. 4,936,835, describing a hypodermic or biopsy needle comprising a bio-absorbable/degradable gelatin cutting/puncturing needle tip. The modified gelatin needle tip disintegrates, thereby rendering the needle useless following single injection. As with the modified needle tip of U.S. Pat. No. 4,976,704, the modified gelatin based needle tip is incapable of application to infusion treatment.
It is apparent that there exists a need for an infusion needle which, concurrent to its principle function of serving as an effective vehicle of medical fluid delivery (or body fluid withdrawal) along with associated requirements of being a medical infusion needle, can be used to prevent, or at least minimize, blood vessel or tissue damage to patients as a result of movement at the junction consisting of the infusion needle tip and the patient's blood vessel or target organ. Additionally, there is a need for such a modified infusion needle whereby there is no potential of microorganism contamination or infection in the patient during infusion treatment, associated with plastic infusion tubes. Moreover, additional and desirable attributes of such an invention of a modified infusion needle include cost effectiveness, and absence of the need for the infusion needle to be part of a mechanism requiring operator manipulation or involvement during the infusion treatment.